Because each individual with autism has their own specific traits and characteristics, it is difficult to encompass a diagnostic test that is all encompassing for all individuals. These personal differences mean that, in order to diagnose, physicians and psychologists must be able to accurately and reliably code a vast array of behaviors and observations. There are no easy, obvious, or exact indicators (especially at such a young age when the child is just beginning to really demonstrate themselves (and their personality) as an individual)

2. Co-occurrence

Autism itself presents as differences in a wide array of settings and skill areas, while it can also be accompanied by other medical or mental conditions. It was reported that as many as 1/3 of autistic people may also become epileptic, while it is also possible that (with genetic or infection-induced autism) it may be accompanied by other learning disabilities, ADHD, depression, or anxiety. All of these conditions may be present, which may make it difficult to distinguish what is causing the differences in the child.

3. Changes with Time

Diagnostic cut-offs have been hard to define because the manifestation of the core impairments and behaviors of autism varies greatly from person to person. As the child grows and develops (just like everyone else) they will change, meaning that their strengths, weaknesses, and abilities may change and adapt over time. The less time a child has to demonstrate certain behavior (some of which have not even developed at such a young age! ie. peer relationships or intense interests) the less accurately observations are able to predict more generalized behavior.

4. Lack of Genetic/Medical “Test”

One of the things that makes a definitive autism diagnosis difficult (even with older individuals), is a lack of a sure genetic or medical test. So far, there has not been a genetic marker to signal a confirmation of autism. Not being able to use our ‘advanced’ science and technology to ‘prove’ what we believe we are seeing makes it difficult to reach a conclusive diagnosis (especially when , at such a young age, we have so little to observe). This means that all tests have to be subjective and cannot just be done with something like a blood test. There are assessments and subjective decisions that have to be made to diagnose, even though it is a considered a neurological disorder.

5. Differential Diagnosis

Autism shares many of its presentations with other conditions, which may make it difficult to distinguish between several different conditions. Other diagnoses such as Mental Retardation, learning disabilities, language disorders, specific developmental disorders or other disorders such as early onset epilepsy, Rett syndrome, or neurodegenerative disorders. Each of these includes some features of Autism that may make it difficult to distinguish. For example, some children may have a learning disability that is the result of neurological deficits or other processing problems, but do not necessarily have the qualifications for Autism. There are also factors such as clumsiness or in-coordination that have their own specific diagnosis. It can be difficult to tease apart which symptoms are caused by a disorder and which are the result of Autism as each can build upon each other. For example, a child who is Autistic may have difficulty with speech, causing them to have social problems, learning difficulties, and communication errors. A different child could have the same problems resulting from difficulty with speech, but they could be dependent on vocal cord malformation or a neurological difference specifically in Broca’s or Wernike’s areas of the brain.

6. ‘Normal’ Development Hard to Distinguish earlier

While child development progresses through several ‘critical periods’ where it is ‘normal’ for a child to have developed a particular skill, child development is not an exact map. Different children develop at different rates, and by limiting the timing of diagnosis so such a young age, it leaves little leeway to normal fluctuations and differences in developmental rates. These symptoms also change over time making some symptoms less or more apparent as time goes on. It is also a multidimensional disorder that has numerous components that differ in each person. Some may have difficulties in one area, such as speech, but excel when given the right tools. Another may have the ability to be very artistic but are not able to succeed in math. What is even more significant is that many traits of Autistics can exist in the normal society, making it hard to tease apart what is considered “abnormal” or “normal.”

7. Diagnosis is subjective to who is evaluating them

Diagnosis is often in young children and is the result of what the parents say they observe. In young children some of the key parts of Autism do not develop fully enough to diagnose until later in childhood. With the increasing demands of parents to diagnose early, it is difficult to deal with facts that some children may just develop later than others. It is also difficult to determine if a child is simply not showing you something or if it is not developed. Diagnosis is also often in abnormal settings making the child possibly alter their behavior. This is similar to psychology studies where behavior can be altered by wearing different clothes or being in different rooms that are unfamiliar. Diagnoses can also have unreliable methods of diagnosis such as some tests that are used to determine how fully children can interact based on the evaluator’s suspicion of their intellectual ability. However, communication is often a barrier in these types of tests.

8. There is a lack of understanding about Autism

There is a lot of lack of understanding of the disease. Some people suspect that there can be early diagnosis in order to provide the most promising future for people with Autism. However, a young diagnosis with intervention makes it hard to tell if the intervention worked really well or if your diagnosis was wrong. There is also lack of physician knowledge to make referrals and public knowledge and stigma that makes Autism such a loathsome thing to some people. They may go at any lengths to avoid a diagnosis of Autism if they really didn’t want to believe it. This has been proven throughout history such as when Mexican workers in the US would not go to medical facilities to receive treatment for TB even though they had all the signs because it was a stigmatized disease. “The DSM-IV provides diagnostic criteria, but it doesn’t provide clinicians with guidelines on how to perform initial screenings or on which tools to use to measure behavior,” is also a factor that shows how little knowledge about Autism there is even in the medical realm.